This application is a national stage filing under 35 U.S.C. xc2xa7 371 of International Application No. PCT/SE98/01720 filed on Sep. 24, 1998, which International Bureau in English on Apr. 1, 1999.
The present invention relates to a marine propeller, a propeller system, an adapter, a set of adapters, and a method of connecting a propeller.
Marine propellers are normally driven by a motor, or an engine, to which the propeller is connected through the medium of an output shaft from a gearbox coupled to the motor. Such motors are manufactured and supplied by a large number of manufacturers, wherewith each manufacturer gives the motor and associated gear housing his/her particular design. This normally results in that a certain propeller will only fit the motor of a particular manufacturer. The decisive factor as to whether or not the propeller can be connected to a given motor is whether or not the output shaft from the motor gearbox can be coupled to the propeller hub, which is normally effected with the aid of a spline coupling. Another deciding factor is whether or not the propeller hub is configured so as to enable it to be fitted in the gearbox opening through which the drive shaft extends. The first aspect will not normally constitute a problem, since the propeller hub is standard for a given power class and the splines identical. On the other hand, the connecting flange on the gearbox may have a different configuration and the output shaft a different length. This is the primary cause of the problem that resides in the propeller hub not being adapted to the connecting flange of the gearbox and/or that the shaft extends too far or not far enough at the point where the hub shall be connected to the gearbox.
It is known from WO 96/05101 and U.S. Pat. No. 4,842,483, for instance, to provide an adapter between the hub splines and the shaft splines in respect of small-craft motors that have different spline dimensions because of different drive powers, for instance, so as to enable one and the same propeller to be connected to drive shafts of mutually different spline dimensions by appropriate adapter selection. However, the solution does not solve the problem of adapting the hub to suit the flange of the gearbox and to the length of the drive shaft.
Seen against this background, the object of the present invention is to enable one and the same propeller to be used with different types of motors with regard to connecting such motors to the propeller, particularly the design of the gearbox connecting flange, and with regard to the length of shaft extending from the gearbox.
The object with respect to the first aspect has been achieved in accordance with the invention by means of a marine propeller, a propeller system, an adapter, and a set of adapters according to the present invention.
Because the propeller is provided with a separate adapter element that is fastened detachably to the hub and has a side adapted to the gearbox flange and the shaft length, one and the same propeller can be connected to any one of several different types of motor by appropriate selection of an adapter element. This obviates the need for a propeller manufacturer or supplier to maintain a large assortment of propellers in order to be able to supply a particular propeller for a particular motor. In principle, it will suffice to have one propeller in each size class and a set of adapter elements that suit different types of motor. This rationalises both manufacture and storage and makes manufacture and storage less expensive.
Because that part of the drive source housing to which the propeller shall be connected is normally comprised of a circular flange positioned about a shaft exit opening in the gearbox, it is suitable to provide the housing-adapting side with an axially directed circular flange. This can then be inserted into the gearbox flange with a small clearance and co-act with said flange to form a sealing casing around the drive shaft. An adapter element of this design thus constitutes a preferred embodiment of the invention.
According to a further preferred embodiment of the invention, the propeller is adjustable so as to enable the propeller blades to be adjusted to other settings in distinct steps and in unison. This widens the field of use in respect of each type of propeller and therewith further contributes towards achieving the object of the invention, to-wit of reducing the number of propellers necessary in one assortment.